Embryonic rat lens epithelial cells will be established in culture and the temporal relationship of lens cell differentiation and induction of cell division studied. We want to define when during the cell cycle commitment to cell differentiation occurs and the consequence of expression of differentiated functions in terms of cell proliferation. Epidermal growth factor (EGF) and insulin have been shown to interact with tissues of the eye and stimulate cell division in vivo and thymidine incorporation into DNA in vitro. In the second phase of our work we want to determine the effects of these agents on lens cell division and differentiation. The final aspect of the proposed studies is the development of methods for automatic separation and isolation of homogeneous populations of undifferentiated and differentiated cell types.